That pain and anger has a way of just creeping up and biting you on the bum when you least need it. As if we need to be reminded of all the crap that happened.
Maybe this is all natural effects and processes of the results of what happened.
I can understand and relate to your frustrations and I am really hoping that a better day will be with you soon.
Hope your sister is making good progress.
Wrap your arms around you, look in the mirror and smile at the person you are - a good one with good beliefs.